CXML
        	    
LAPACK version 3.0
zpttrs(3)

PURPOSE
  ZPTTRS - solve a tridiagonal system of the form A * X = B using the
  factorization A = U'*D*U or A = L*D*L' computed by ZPTTRF

SYNTAX
  SUBROUTINE ZPTTRS( UPLO, N, NRHS, D, E, B, LDB, INFO )

      CHARACTER	     UPLO

      INTEGER	     INFO, LDB, N, NRHS

      DOUBLE	     PRECISION D( * )

      COMPLEX*16     B( LDB, * ), E( * )

DESCRIPTION
  ZPTTRS solves a tridiagonal system of the form A * X = B using the
  factorization A = U'*D*U or A = L*D*L' computed by ZPTTRF. D is a diagonal
  matrix specified in the vector D, U (or L) is a unit bidiagonal matrix
  whose superdiagonal (subdiagonal) is specified in the vector E, and X and B
  are N by NRHS matrices.

ARGUMENTS
  UPLO	  (input) CHARACTER*1
	  Specifies the form of the factorization and whether the vector E is
	  the superdiagonal of the upper bidiagonal factor U or the
	  subdiagonal of the lower bidiagonal factor L.	 = 'U':	 A = U'*D*U,
	  E is the superdiagonal of U
	  = 'L':  A = L*D*L', E is the subdiagonal of L

  N	  (input) INTEGER
	  The order of the tridiagonal matrix A.  N >= 0.

  NRHS	  (input) INTEGER
	  The number of right hand sides, i.e., the number of columns of the
	  matrix B.  NRHS >= 0.

  D	  (input) DOUBLE PRECISION array, dimension (N)
	  The n diagonal elements of the diagonal matrix D from the
	  factorization A = U'*D*U or A = L*D*L'.

  E	  (input) COMPLEX*16 array, dimension (N-1)
	  If UPLO = 'U', the (n-1) superdiagonal elements of the unit
	  bidiagonal factor U from the factorization A = U'*D*U.  If UPLO =
	  'L', the (n-1) subdiagonal elements of the unit bidiagonal factor L
	  from the factorization A = L*D*L'.

  B	  (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
	  On entry, the right hand side vectors B for the system of linear
	  equations.  On exit, the solution vectors, X.

  LDB	  (input) INTEGER
	  The leading dimension of the array B.	 LDB >= max(1,N).

  INFO	  (output) INTEGER
	  = 0: successful exit
	  < 0: if INFO = -k, the k-th argument had an illegal value